Rod chucking device for a perforator for perforating a pig iron discharge opening in a blast furnace

ABSTRACT

A rod chucking device for a perforator for perforating a pig iron discharge opening being adapted to mount exchangeably perforating rods for perforation work, such as drill rods, blanking rods and the like to the tip end of an impact rod. The chucking device has a cotter movable between an engage position and disengage position in order to fix the perforating rod inserted into a rod insert hole of a socket. A spring is engaged with the cotter for urging the cotter toward the engage position. In order to prevent deterioration of the spring through vibration and heat during the operation, chilling air passage from the impact rod to the perforating rod is separated to form an air passage to chill the spring.

TECHNICAL FIELD

This invention relates to a perforator for perforating a pig irondischarge opening in a blast furnance. Specifically, this inventionpertains to a rod chucking device for holding a perforating rod of theperforator, such as drill rod, blanking rod and the like.

BACKGROUND ART

Conventionally, an opening for discharging pig iron is formed byperforating wall of the blast furnance by means of a perforator. In thiscase, the perforator comprises a perforating rod, such as drill rod andblanking rod to thereby perform the perforating work. Since theperforating rod wears down remarkably through the perforating work, theperforating rod is necessary to be exchanged frequently and theexchanging work should be done under high temperature of the rod. Achucking device is provided in order to engage the perforating rod withan actuator or impact rod. In conventional chucking devices, thechucking device normally has a structure in which a socket is connectedto the impact rod of the perforator, a perforating rod is inserted intoa rod hole of the socket to be fixed thereto and the perforating rod islocked through a cotter. In this case, the exchange work of theperforating rod are usually carried out by hand.

It is preferred that the exchange work of the perforating rod isautomated because of a hard work under bad conditions, such as hightemperature, high dust. For the purpose, it is necessary that the cotteris movable between an engage position and disengage position and thecotter is urged against the engage position by a spring. In theconventional rod chucking device, however, vigorous vibrations aretransmitted to the socket through the impact rod to vibrate the springviolently during operation As the result the spring is heated to thetemperature of 300° C.-400° C. within a short time to produce adeterioration of material, spring constant and tensile strengthresulting in losing spring function, fracture in only 20-30 minute use,and increase of wear.

Under these circumstances, it is suggested that materials having a highstrength properties at high temperature, such as Inconel, are employedfor the spring. However, since the spring of Inconel is very expensiveand the spring is necessary to be exchanged frequently because of itsshort life, it will not be allowable in the cost.

DISCLOSURE OF THE INVENTION

An object of the invention is to provide a rod chucking device for aperforator for forming pig iron discharge openings of a blast furnancewhich can solve the above problem.

A further object of the invention is to provide a rod chucking device ofwhich perforating rod can be exchanged automatically and is inexpensiveand durable.

In order to accomplish the above objects, the rod chucking device inaccordance with the present invention characterized by a socket beingconnected with a tip end portion of a impact rod of a perforator at therear end portion, a rod insert hole being formed at the front portion ofthe socket to mount the perforating rod thereto, a cotter for securingthe perforating rod to a cotter hole formed in the socket perpendicularto the rod insert hole being disposed movably between an engage positionand a disengage position, a spring being provided for urging the cotterto the engage position, a rod connecting hole for connecting the impactrod to the socket being communicated with a spring mount hole through anair passage, air from the impact rod being injected to the spring mounthole through the air passage to thereby chill the spring.

According to the present invention, a part of the air supplied to theperforating rod through the impact rod is always supplied for chillingthe spring to thereby restrain undesirable heating of the spring toimprove the duration thereof. Further, the cotter is adapted to movebetween the engage position and the disengage position, and be urgedagainst the engage position so that automating of exchange of theperforating rods can be readily accomplished.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is longitudinal sectional view of a rod chucking device forperforating according to the embodiment of the present invention.

FIG. 2 is a sectional view taken by line II--II.

FIG. 3 is a similar view as FIG. 2 showing a disengage position of thecotter.

FIG. 4 is a bottom view of the cotter.

BEST MODE FOR CARRYING OUT THE INVENTION

A rod chucking device for perforating pig iron discharge openings of ablast furnace is shown in drawings. The rod chucking device comprises asocket connected to a tip end portion of an impact rod 1 of a perforator(not shown), a cotter 4 for securing a perforating rod 3 to the socket 2with the perforating rod 3 mounted to the socket 2 at the base portion,a coil spring for urging the cotter, and a cotter guide.

A rod connecting hole 7 is formed in the rear portion of the socket 2for connecting to the impact rod 1. The tip end portion of the impactrod 1 is screwed into the rod connecting hole 7 to connect to the socket2. A rod insert hole 8 is formed in the front portion of the socket 2.The rod insert hole 8 is concentric to the rod connecting hole 7. In thesocket 2, there is formed a cotter hole 9 perpendicular to the rodinsert hole 8 and connected to the hole 8. A spring mount hole 10 isdisposed parallel to the cotter 4 at the upper portion of the cotterhole 9.

The cotter hole 9 has the substantially square configuration in sectionin the area above the rod insert hole 8 at one side of the hole 9 andextends upward to be communicated with the spring mount hole 10 at theother side.

There is disposed the cotter 4 movably in the cotter hole 9. A coilspring 5 is mounted between a spring seat portion 4a of the cotter 4projecting into the spring mount hole 10 and an end wall 10a of the hole10 through end plates 11 so that the cotter is urged in the outerwarddirection (in the left direction in FIG. 2).

The base portion of the perforating rod 3 is adapted to be inserted intothe rod insert hole 8 of the socket 2 to be engaged with the cotter 4.When necessary, the perforating rod 3 can be removed as described below.An arched recess 12 is formed at the lower side of the cotter 4 forallowing the perforating rod 3 to pass through when the cotter 4 islocated at a disengage position where the cotter 4 moves rightmost (seeFIG. 3). On the other hand, an engaging portion 14 is formed on thecotter 4 for engaging with an engaging recess 13 of the perforating rod3 when the cotter 4 is located in an engage position where the cotter 4moves leftmost (see FIG. 2). There is, further formed an arched slantguide surface 16 at the lower side of the cotter for abutting to thebase end portion 15 of the perforating rod 3 when the rod is insertedinto the rod insert hole 8 so that the cotter can move to the disengageposition. The upper end 16a of the guide surface 16 is smoothlycontinued on the upper surface of the rod insert recess 12. The cotter 4is further provided with a slant surface 17 inclined in the rightdirection in FIG. 2 from the upper portion of the recess 12. The slantsurface 17 is inclined at 20-30 deg to the bottom surface 13a of theengaging recess 13 formed on the perforating 3 when the cotter 4 islocated in the engage position.

According to the above structure, when the perforating rod 3 is insertedinto the socket 2 to mount thereto, the guide surface 16 is pushed bythe base end portion 15 of the perforating rod so that the cotter isforced to move to the disengage portion against the spring 5. Then, therod insert recess 12 is overlapped with the rod insert hole 8 so thatthe perforating rod 3 can be inserted to be mounted on the socket 2.

When the base end surface 18 of the rod 3 is abutted on the end surface19 of the rod insert hole 8 and the engaging recess 13 of the rod 3 isaligned with the cotter hole 9, the cotter 4 is pressed by the spring 5to move to the engage position to thereby engage the engaging portion 14with the engaging recess 13 so that the perforating rod 3 is secured tothe socket 2 by means of the cotter 4.

When the perforating rod is removed from the socket 2, the socket 2 isrotated in the direction of arrow in FIG. 2 by the rotation force of theimpact rod 1 with the perforating rod 3 being fixed by a clamp or thelike (not shown). Consequently, the slant surface 17 of the cotter 4 isabutted on the bottom surface 13a of the engaging recess 13 to bepressed by the bottom surface 13a so that the cotter moves to thedisengage position (see FIG. 3). In turn, the socket 2 moves backwardwith the impact rod 1, or the perforating rod 3 moves forward so thatthe perforating rod 3 can be removed from the socket 2.

A cotter guide 6 is provided around the socket 2 at the front portionthereof and abutted on the outer surface of the cotter to hold thecotter 4. The cotter guide 6 is fixed to the socket 2 by means of boltsor the like. When the cotter guide 6 moves backward, the cotter 4 andspring 5 are adapted to be removed from the socket 2.

Viewing that the spring 5 is fairly heated because of a violentvibration of the socket 2 from the impact rod 1, a chill means forchilling the spring 5 is provided as described below.

When pig iron discharge openings are formed in a wall of a blast furnaceby means of a perforator, in the first stage, a drill rod 3a is employedfor perforating the wall as a perforating rod 3. In the last stage, ablanking rod is employed to open the openings as the perforating rod 3.In this case, in order to chill the drill rod 3a and remove dustresulting from the perforation, air is introduced from the perforator tothe drill rod 3a.

The air from the perforator is supplied from an air passage 20 formed inthe impact rod 1, passes through a communicating passage 21 forcommunicating the rod connecting hole 7 and the rod insert hole 8, andis introduced to an air passage 22 in the drill rod 3a.

An air passage 23 is formed in the socket 2 for conducting a part of theair to the spring mount hole 10 wherein the starting portion of the airpassage 23 is opened to the communicating passage 21 and the end portionof the air passage 23 is opened to the spring hole.

The air passage 23 can be constituted by pipings.

In the above constitution, the air is supplied by way of the air passagein the impact rod 20, the communicating passage 21 and the air passage23 to be impacted into the spring mount hole 10 to thereby chill thewhole of the spring 5 effectively. Then, the air is conducted fromopening 24 under the spring mount hole 10 to the cotter hole 9, and fromthe spring mount hole 10 to gaps around the spring seat 4a anddischarged from gaps between the socket 2 and the cotter guide 6.

When the blanking rod (not shown) is employed for the perforating rod 3,it is not necessary to supply the chilling air to the blanking rod.However, the air is supplied to the spring mount hole 10 in the manneras mentioned above.

Thus, the spring 5 is always chilled by the air. Therefore undesirableheating of the spring 5 be avoided so that the spring 5 can give fullplay to the performance and improve the durability.

We claim:
 1. A rod chucking device for a perforator for perforating apig iron discharge in a blast furnace, said rod chucking devicecomprisinga rod insert hole formed in a front portion of said socket formounting a perforating rod, said perforating rod being inserted intosaid rod insert hole, a cotter for securing said perforating rod, saidcotter being slidably mounted in a cotter hole formed in said socketperpendicularly to said rod insert hole so that said perforating rod isadapted to be locked in said socket, said cotter being disposed movablybetween an engage position and a disengage position, a spring for urgingsaid cotter towards said engage position, a rod connecting hole forconnecting said impact rod with said socket, said rod connecting holebeing in communication with a spring mount hole through an air passageso that air supplied from said impact rod is injected into said springmount hole through said air passage to chill said spring.
 2. The rodchucking device in accordance with claim 1 wherein said air passage isseparate from other air passages communicating between said impact rodand said perforating rod.
 3. The rod chucking device in accordance withclaim 1 wherein said air passage is formed in said socket.
 4. The rodchucking device in accordance with claim 1 wherein a cam-shaped guidesurface is formed on said cotter for engaging a tip end portion of saidperforating rod when said perforating rod is inserted into said rodinsert hole of said socket, said cam-shaped guide surface being adaptedto produce a driving force for moving said cotter to said disengageposition.
 5. The rod chucking device in accordance with claim 4 whereina rod insert recess is formed in said cotter with said recess beingoverlapped with said rod insert hole.
 6. The rod chucking device inaccordance with claim 5 wherein an engaging recess is formed in theperforating rod, said engaging recess being aligned with said cotter ata position where said perforating rod is inserted into said rod inserthole.
 7. The rod chucking device in accordance with claim 4 whereinmeans for pressing said cotter opposite to said disengage position isprovided when said perforating rod rotates relative to said socket.